docs: rename project to codext

Author: Loongphy

README.md

@@ -1,12 +1,12 @@
-# Codex
+# Codext
+
+An opinionated Codex CLI. This is strictly a personal hobby project, forked from openai/codex.
 
 ![Codex build](https://img.shields.io/static/v1?label=codex%20build&message=rust-v0.111.0-36ab73925&color=2ea043)
 
 ![TUI](
 https://github.com/user-attachments/assets/127abbc2-cb30-4d6e-8a81-ce707260c045)
 
-This is strictly a personal hobby project, forked from [openai/codex](https://github.com/openai/codex).
-
 ## Quick Start
 
 ```shell